Automatic pipette-system arrangement, the action of which is controlled, for transferring liquid from one test to another



NOV. 26, 1968 JUNGNER 3,413,097

AUTOMATIC PIPETTE-SYSTEM ARRANGEMENT, THE ACTION OF WHICH IS CONTROLLED, FOR TRANSFERRING LIQUID FROM ONE TEST TO ANOTHER Filed May 18, 1965 United States Patent 3,413,097 AUTOMATIC PIPETTE-SYSTEM ARRANGEMENT, THE ACTION OF WHICH IS CONTROLLED, FOR TRANSFERRING LIQUID FROM ONE TEST TO ANOTHER Olof Gunnar Hugo Jungner, Hovas, Sweden, assignor to Centrala Automationslaboratoriet AB Calab, Stockholm, Sweden Filed May 18, 1965, Ser. No. 456,791 Claims priority, application Sweden, May 21, 1964, 6,171/ 64 3 Claims. (Cl. 23-292) ABSTRACT OF THE DISCLOSURE An automatic pipetting arrangement for transferring fluid from one test tube to another provides movement of a vertical pipette holder in successive axial, then lateral, and then axial steps, the axial movements taking place in opposite directions. The arrangement includes a pair of rotatably driven lever arms each having a longitudinal slot therein. A pair of pins disposed for movement within the slots and secured to the holder ride in an inverted U- shaped track and trace out the prescribed movement of the holder upon rotation of the lever arms.

The present invention relates to an automatic pipettesystem arrangement, the action of which is so controlled that the transfer of liquid from one test tube to another can be eifected automatically by means of said arrangement. In many medicinal and industrial methods and laboratory processes, liquid is transferred from one test tube to another by means of a pipette. In a known pipette arrangement a tube is used which takes the form of an upwardly and downwardly bent U, the one branch of which is used as a pipette whereas the other is immersed into a vessel containing fluid, which vessel for the purpose of siphoning a definite volume of fluid into the pipe can be lowered a certain distance corresponding to the amount of fluid to be drawn into said pipe thereby causing a vacuum in the pipe. The assumption is that a vessel containing the liquid to be siphoned by the pipette arrangement is simultaneously positioned around the branch serving as a pipette, said pipette being immersed in this liquid. Thereafter the vessel or the test tube into which the liquid is to be placed is positioned under the siphoning branch of the U-shaped pipe and a three way valve in the connecting pipe between the two branches is opened so that the siphoned fluid can flow out into the test tube.

This siphoning process using an arrangement of pipettes is, however, relatively time wasting and presupposes that test tubes, alternately containing both the fluids required for the reaction in question are moved forward to the pipetting apparatus one after the other. The present invention relates to an automatic siphoning arrangement using a pipette system in which both test tubes containing the various reagent liquids or substances can be added to the apparatus at the same time in pairs or in two parallel series, and comprises mainly in that the pipette, which is connected to a suction pipe, is arranged to be retained by a substantially vertically arranged holder, whichwith the assistance of at least one lever rotatable about a shaft at a right angle to the plane of the holder--can be brought first a lineal movement vertically upwards, thereafter a substantially lineal lateral movement at right angles, and finally once again a movement in a vertical direction but this time downwards, or vice versa.

According to one embodiment of the invention, the lever controlling the movement of the holder is thereby securely mounted at one end to the rotating shaft and at 3,413,097 Patented Nov. 26, 1968 its other end provided with a pin, by which the holder is controlled, which pin is arranged to be moved in a groove in the form of an upturned and downturned U in a plate suitably made of plastic-which plate at the same time supports the rotatable shaft-and partly displaceably arranged in a longitudinal track in the lever rotatably about the rotating shaft.

According to a further development of the invention the holder is also thereby at its other end guided by a pin capable of being guided in another U-shaped groove, which pin in the same way as the above mentioned pin is displaceably mounted in a rotable lever which rotates together with a second shaft at right angles to the plane of the holder. Both of the rotatable levers, in order to attain the aforementioned movement of the pipette holder, are thereby connected so that they move synchronously.

A suitable embodiment of the invention consists in that a reversible motor is arranged on a plate arranged upon the same, which motor drives a gear which in turn drives two more gears of which one drives the one rotatable shaft and the other the other rotatable shaft for both the aforementioned rotatable levers.

End position contacts are arranged so as to obtain the oscillating reciprocating movements of the motor, which contacts are capable of being mounted on the aforementioned plate and which are arranged to be actuated by cam members on any of the aforementioned gears.

By providing the U-shaped track with a larger or a smaller distance between both the vertical branches, the time taken for the horizontal movement of the holder arrangement can be made longer or shorter so that needed time remains at the disposal for releasing the suction pipe of the pipette suction arrangement and for a possible connection of compressed air for the purpose of flushing out the fluid in the other pipette suction pipe.

The invention will now be more closely described in connection with the attached drawing on which:

FIG. 1 shows the arrangement in perspective seen obliquely from the front, whereas FIG. 2 shows the interior of the arrangement, i.e. the driving arrangement for moving the tube up and down. The suction pump has not been reproduced in any of the figures for the purpose of illustration.

Two similarly U-shaped tracks 1 and 2 are arranged on the front of the arrangement on its upper and lower section, on which track the guide pins (not shown) of the suction pipe holder 3, slide. The guide pins are further guided by means of slots 4 and 5 disposed in the rotating levers 6 and 7. The levers 6 and 7 are secured on the shafts 8 and 9 respectively (FIG. 2). Moreover each of said shafts 8 and 9 are fitted with gear wheels 10 and 11 respectively. Both the gear wheels are identical with respect to the number of teeth, teeth-size and diameter. One of the gear wheels is provided with a cam mounted in a suitable position, which cam actuates end contacts 12 and 13 respectively in the driving circuit for a driving motor intended for the shafts 8 and 9 as well as for the suction pipe holder 3. The contacts are thereby actuated when the suction pipe holder occupies its lowest right hand or left hand position respectively. The end contacts 12 and 13 and possibly a timing device (not shown) influence the motor current in a desired manner. The motor 14 has reversible rotation direction and drives, via a gear reduction system, the cog wheel 15 situated between the cog wheels 10 and 11, said cog wheel 15 driving said gear wheels 10 and 11.

The operation of the arrangement is as follows: The pipette suction pipe, as shown by broken lines in FIG. 1, which by means of the suction hose, similarly indicated by broken lines, is connected with the suction arrangement, is secured in the suction pipe holder 3. Placed at a suitable height under the left hand branch of the tracks 1 and 2 in FIG. 1 is a suitable shaped vessel containing the test fluid which is to be transferred to the test tube for example, which test tube is placed under the right hand branch in FIG. 1 of the tracks 1 and 2. In FIG. 1 a test tube has been indicated by a broken line. The suction pipe is lowered into the vessel containing the test fluid by rotating the levers 6 and 7, driven by means of the motor and gear wheels, counter-clockwise. The motor 14 stops for a certain period of time, possibly an adjusted period, which is decisive for the siphoned volume of fluid, whereafter the motor in restarted in the reverse direction of rotation, the suction pipe is raised, moved to the right, lowered and remains, possibly only a certain time, directly above the test tube. The suction arrangement, which has been in operation the whole time, is disconnected, the test fluid runs out into the test tube, the motor 14 is restarted, once again in a reversed movement of direction, at the same time as the suction arrangement is reconnected and the suction tube once again moved down into the vessel containing the test fluid. In between times, the just filled test tube is replaced by a new test tube, possibly automatically, and the process is repeated.

One requirement for using the pipette-process suction arrangement is naturally that the level in the test tubes, from which the fluid is removed, is substantially the same. When great demand is placed on accuracy or lesser possibility of retaining equal levels, the immersion speed of the pipette suction arrangement is raised, although a limit is thereby imposed due to the fact that the immersion of the pipette suction pipe means a certain shock action of the fluid, a flop, which can unfavou'rably influence the measuring result.

Although the invention is described in connection to one embodiment of the same, it can, however, be varied arbitrarily within the scope of the following claims.

What I claim is:

1. An automatic pipetting arrangement for transferring fluid from one test tube to another, comprising pipetting means connected to a suction source, a substantially vertical holder for holding said pipetting means, at least two pins for mounting said holder, said pins forming right angles with said holder, at least two levers, each lever having a longitudinal slot therein for receiving one of said pins, said slots permitting movement of said pins along the lengths of said levers, shaft means for rotatably driving said levers, said shaft means forming a right angle with said holder, stationary track means comprising inverted U-shaped tracks for engaging with each of said pins, and means for driving said shaft means and said associated lever means in synchronism so as to impart three successive movements to said holder, said successive movements comprising an axial movement, a lateral movement and an axial movement.

2. An automatic pipetting arrangement as claimed in claim 1 wherein said driving means comprises a reversible electric motor.

3. An automatic pipetting arrangement as claimed in claim 1 further comprising compressed air means for blowing out the fluid in a test tube during the lateral movement of said holder, the length of the yoke portion of said inverted U-shaped tracks being sufficient to permit the blowing out operation.

References Cited UNITED STATES PATENTS 2,624,656 1/1953 Andrews et al. 23259 3,143,393 8/1964 De Seguin Des Hons 23253 3,178,266 4/1965 Anthon 23-253 3,192,968 7/1965 Baruch et al. 23--259 XR 3,193,358 7/1965 Baruch 14ll35 XR 3,193,359 7/1965 Baruch et al. l41135 XR MORRIS O. WOLK, Primary Examiner.

R. E. SERWIN, Assistant Examiner. 

